Computer Studies Scheme of Work for SS2 Second Term
SCHEME OF WORK
WEEK 1 COMPUTER DATA CONVERSION I
WEEK 2 COMPUTER DATA CONVERSION (BUS)
WEEK 3 COMPUTER FILES
WEEK 4 METHODS OF ACCESSING FILES
WEEK 5 HANDLING COMPUTER FILES
WEEK 6 FILE INSECURITY
WEEK 7 WORD PROCESSING
Below are the 2022 complete SS2 Second Term Computer Science Lesson Note
SECOND Term SS2 Computer Science Lesson
Topic: Computer Data Conversion
Computer Data Conversion
Data conversion is the conversion of computer data from one format to another. Throughout a computer environment, data is encoded in a variety of ways. For example,computer hardware is built on the basis of certain standards, which requires that data contains, for example, parity bit checks. Similarly, the operating system is predicated on certain standards for data and file handling. Furthermore, each computer program handles data in a different manner. Whenever any one of these variables is changed, data must be converted in some way before it can be used by a different computer, operating system or program.
REGISTERS: Registers are used to quickly accept, store and transfer data and instructions that are being used immediately by the CPU. There are different types of registers, accumulators, program counter, memory data register, memory buffer register. Registers are temporary storage area for instructions or data. They are not a part of memory; rather they are special additional storage locations that offer the advantage of speed. It works under the direction of the control unit to accept, hold, and transfer instructions or data and perform arithmetic or logical comparisons at high speed. To learn more, Click here
Topic: Computer Data Conversion II
Computer Data Conversion
BUS: A bus is a communication system that transfers data between components inside a computer or between computers. This expression covers all related hardware components (wire optical fibre) and ware including communication protocols. A bus is a transmission path on which signals are dropped off or picked up at every device attached to the line.
A bus, in computing is a set of physical connections (cables, printed circuits etc.) which can be shared by multiple hardware components in order to communicate with one another. The purpose of bus is to reduce the number of pathways needed for communication between the components, by carrying out all communications over a single data channel.
Early computer buses were parallel electrical wires with multiple connections, but the term is now used for physical arrangement that provides the same logical functionality as a parallel electrical bus. Modern computer buses can use both parallel and serial connections and can be wired in either a multitrip and electrical parallel and or falsy main topology or connected by switch hubs as in the case of USB. To learn more, Click here
Topic: Computer Files
A computer file is a resource for storing information which is available to a computer program and is usually based on some kind of durable storage. Computer file can be considered as the modern counterpart of paper documents which are traditionally kept in offices and libraries. A file is “durable” in the sense that it remains available for other programs to use after the program that created it has finished executing.
Topic: Methods of Accessing Files
File organization is a way of organizing the data or records in a file. It does not refer to how files are organised in folders but how the contents of a file are added not accessed. There are several types of file organisation methods. The most common of them are sequential, relative and indexed. They differ in how easily records can be accessed and the complexity in which records can be organized. In modern computer systems, files are typically accessed using names also known as the file name. Most computers organize files into hierarchies using folders, directories or catalogues. The concept is the same irrespective of the terminology used. Each folder can contain an arbitrary number of files, and it can also contain other folders. These other folders are referred to as subfolders. Subfolders can contain still more files and folders and so on, thus building a tree-like structure in which one “master folder” can contain any number of levels of other folders and files. To learn more, Click here
Topic: Handling Computer Files
A file is abstract; to define a file properly we need to consider the operation that can be performed on the files. There are six basic file operations that can be performed by the OS. The OS can provide system calls to create, write, read, re-position, delete and truncate files. All information in a file is always in binary form or a series of ones and zeros. A document includes any file you have created. It can be a true text document, sound file, graphics, images, or any other type of information the computer can create store, or size from the internet.
1. Creating a file: Two steps are necessary to create a file.
- Space in the file system must be found for the file.
- An entry for the new file must be made in the directory.
- Writing a file: To write a file, we make a system call specifying both the name of the file and the information to be written in the file. The system must keep a write pointer to the location in the file where the next write is to take place.
- Deleting a file: To delete a file, we search the directory for the named file. Having found the associated directory entry, we release all file spaces so that it can be re-used by other files and erase the directory entry. To learn more, Click here
This is the concept that a file is always vulnerable and is prone to be lost or missing in the computer. File security is a feature of your file system which controls which users can access which files, and places limitations on what users can do to various files in your computer.
Effect of File Insecurity
- Loss of Data: Computer users and experts often experience data loss when files are destroyed, and sometimes there is no hope of recovery and this is as a result of files being tampered with on the computer or through virus invasion or sudden crash of the operating system.
- Overwriting: This is a process of writing a binary set of data on memory. Data that has been overwritten is generally considered to be unrecoverable. To learn more, Click here
Topic: Word Processing
A word processor enables you to create a document, store it electronically on a disk, display it on a screen, modify it by entering commands and characters from the keyboard and print it out from a printer. Using a computer to create, edit and print documents from all kinds of computer applications is termed word processing. Word Processing is the use of computer technology to create, edit, and print text–based documents. It is used for communicating text–based documents such as Letters, Reports, Memos, Manuscripts and other official documents.
Examples of Word Processors
- Microsoft word
- Word Perfect. To learn more, Click here